Antenatal Care and Screening Flashcards
How common is morning sickness?
Affects 80-85% of women
When is morning sickness worse?
- Early in pregnancy
- Conditions where BHCG is higher (twins, molar pregnanct etc.)
What can morning sickness progress to?
Hyperemesis gravidarum
How can morning sickness be managed?
Sometimes requires rehydration therapies and steroids
How does pregnancy affect cardiac output?
- Increases by 30-50%
- Heart rate increase from 70-90bpm
- Palpitations are common
- At term blood flow to the uterus must exceed 1L per minute
Why does BP drop in the 2nd trimester?
- Expansion of the uteroplacental circulation
- A fall in systemic vascular resistance
- A reduction in blood viscosity
- A reduction in sensitivity to angiotensin
- BP usually returns to normal in the third trimester
How does pregnancy affect urine output?
- Increased urine output
- Renal plasma flow increases by 25-50%
- GFR increases by 50%
- Serum urea and creatinine decreases
Why are UTIs more common in pregnancy?
- There is an increase in urinary stasis (less chance of the bladder completely voiding)
- Hydronephrosis is physiological in the third trimester and makes pyelonephritis more common
- Can be associated with preterm labour so important to treat
What haematological changes occur during pregnancy?
- Physiological anaemia
- Plasma volume increases by about 50% and RBC mass by about 25%
- Drop in haemoglobin by dilution from 133-121g/L
- Iron requirements are increased by 1g during pregnancy
- WBC increase slightly to 9000-12,000/uL
- Platelet count falls by dilution
What respiratory changes occur during pregnancy?
Progesterone acts centrally to reduce CO2
- Increases tidal volume
- Increases respiratory rate
- Increases plasma pH
- O2 consumption increase by 20%
- Plasma PO2 is unchanged
- Hyperaemia of respiratory mucous membranes
What GI changes occur during pregnancy?
- Oesophageal peristalsis is reduced
- Gastric emptying sloes
- Cardiac sphincter relaxes
- GI motility is reduced due to increased progesterone and decreased motilin
Ideally, who should receive pre-pregnancy counselling?
All women
What are the top 5 causes of maternal death?
- Cardiac disease
- Sepsis
- Thrombosis
- Neurological
- Psychiatric
What is involved in pre-pregnancy counselling?
- Improve diet
- Optimise BMI
- Reduce alcohol intake
- Smoking cessation
- Folic acid
- Confirm immunity to rubella
How should folic acid be taken?
- 400mcg
- Advised to start 3 months before conception
- Can significantly reduce the risk of neural tube defects
What is involved inn pre-pregnancy counselling for known medical problems?
- Optimise maternal health
- Psychiatric health is important
- Stop/Change any unsuitable drugs
- Advise regarding complications associated with maternal medical problems
- Occasionally advise against pregnancy
What maternal previous pregnancy problems should be addressed in pre-pregnancy counselling?
- Counsel regarding risk of recurrence
- Caesarean Section
- DVT
- Pre-eclampsia (aspirin)
What actions can reduce maternal complications?
- Thromboprophylaxis
- Low dose aspirin
What foetal previous pregnancy problems should be addressed in pre-pregnancy counselling?
Counsel regarding risk of recurrence
- Pre-term delivery
- Intrauterine growth restriction
- Foetal abnormality
What actions can reduce foetal complications?
- Treatment of infection
- High dose folic acid
- Low dose aspirin
Why is antenatal examination carried out?
High quality antenatal care reduced foetal and maternal mortality by identifying problems
What problems can be identified in the antenatal examination?
Mother
- Problems such as pre-existing or developing illness
- ‘Minor’ problems of pregnancy such as anaemia
Foetus
- Small for gestational age
- Foetal abnormality
Social
- Support
- Domestic violence
- Psychiatric Illness
What is involved in the antenatal examination?
- Routine enquiry
- Blood pressure
- Urinalysis
- Abdominal palpation
- Determine foetal lie
- Listen to foetal heartbeat
Why is abdominal palpation carried out?
- Assess symphyseal fundal height (SFH)
- Estimate size of baby
- Estimate liquor volume
What does antenatal screening allow?
Allows conditions to be detected early in a symptomless population to be treated for mother/baby
What infections are screened for in pregnancy?
- Hepatitis B (can provide passive and active immunisation for baby)
- Syphilis (easily treated with penicillin)
- HIV (vertical transmission can be reduced)
- UTI (by MSSU)
- Rubella
How can congenital rubella syndrome present?
- Mental handicap
- Blindness
- Deafness
- Heart defects
What does congenital syphilis cause?
- IUGR
- Hepato-splenomegaly
- Anaemia
- Thrombocytopenia
- Skin rashes
What haematological screening is carried out?
- Screen for iron deficiency anaemia
- Isoimmunisation including Rhesus disease, anti-C and anti-kell
What is rhesus disease?
- Rhesus negative mum has rhesus positive baby.
- Mum develops anti-D antibodies
- Sensitising event
- Subsequent pregnancy mum’s antibodies will cross the placenta and attack rhesus positive baby
What is the purpose of the first ultrasound scan?
- Ensure pregnancy viable
- Multiple pregnancy
- Identify abnormalities incompatible with life
- Offer and carry out Down’s syndrome screening
What is a detailed anomaly scan?
- Systematic structural review of baby
- Not possible to identify all problems
- Can identify problems that need intrauterine or postnatal treatment
What is Down syndrome?
Down Syndrome is a chromosomal abnormality characterised by 3 copies of chromosome 21
What is the overall risk of Down syndrome?
1 in 700
What are some risk factors for Down syndrome?
- Increasing maternal age
- Personal or family history of chromosomal abnormality
What must parents be aware of before screening for Down syndrome?
Women and their partners must be aware prior to any screening taking place that tests for foetal abnormality only provide a risk of their baby being affected.
What first trimester screening for Down syndrome is there?
- Carried out at 10 -14 weeks gestation
- Uses maternal risk factors, serum -human chorionic gonadotrophin (-hCG) and pregnancy associated plasma protein A (PAPP-A) and fetal nuchal translucency (NT) measurement
- Detection rate for Trisomy 21 of ~90%, invasive testing rate of 5%
Where are nuchal translucency measurements taken from?
Between the crown and the rump lengths of 45-84mm
When does nuchal translucency increase?
Nuchal translucency increases with gestational age
and the incidence of chromosomal and other
abnormalities is related to the size, rather than the
appearance of NT.
What happens with a high risk NT result for Down syndrome?
- Further testing is offered if risk of Down’s syndrome is >1 in 150
- CVS
- Amniocentesis
- Non-invasive prenatal testing
When is CVS carried out?
- Between weeks 10 and 14
- 1-2% risk of miscarriage
When is amniocentesis carried out?
- Week 15 onwards
- ~1% risk of miscarriage
How is non-invasive prenatal testing carried out?
- Maternal blood taken
- Can detect fetal cell free DNA
- Can look for chromosomal trisomies
- Not offered on NHS
- If high risk, still recommended to have invasive testing to confirm
What should those at high risk of neural tube defects be advised?
5mg of folic acid to reduce risk
How can neural tube defects be screened for?
-Not routinely offered since introduction of first trimester screening
-First trimester ultrasound to detect anencephaly and sometimes spina bifida (variants of NTD)
-Second trimester biochemical screening(carried out if not able to get NT measurement,
Maternal serum is tested for alpha fetoprotein, >2.0MoM is high risk and warrants investigation)
-Second trimester (20 week) ultrasound will detect >90% of NTD
What is the purpose of the 2nd trimester ultrasound?
- To detect foetal abnormality
- Good test for major structural abnormalities but not chromosomal abnormalities
